A valve timing controller includes a first rotary element to rotate in response to the movement of one of a crankshaft and a camshaft and a second rotary element to rotate in response to the movement of the other of the crankshaft and the camshaft. The controller changes a relative rotation phase between the rotary elements by a link mechanism to adjust valve timing.
JP-2005-48707A (U.S. Pat. No. 6,883,482 B2) discloses a device provided with two groups of link mechanisms that are constituted by combining a first link linked to a first rotary element by a revolute pair and a second link linked to a second rotary element and the first link by a revolute pair. Here, the link mechanisms in the respective groups are arranged in the rotational direction of the first and second rotational elements, thereby controlling off-balance in rotation due to inclination of these rotational elements with respect to the rotational axis.
When the first link of the link mechanism in each group is retained between the second link and the first rotary element in the same group, an area of a portion retained in the first link becomes possibly smaller depending on an arrangement state of the links. In this case, a portion which is not retained by the first link is more likely to be shifted in the rotational axis direction of the first and second rotary elements, causing a possible inclination of the first link to the rotational axis of the rotary elements. Such inclination of the first link is undesirable because it becomes the cause of interrupting an operation of the link mechanism, resultantly a valve timing adjustment.